1. Field of the Invention
The present invention relates generally to a magnetic spring having a plurality of permanent magnets and, in particular but not exclusively, to an energy extracting mechanism provided with a magnetic spring having negative damping characteristics by utilizing a repulsive force of a plurality of permanent magnets.
2. Description of Related Art
Various pressure mechanisms are widely used today. A press for performing pressure molding upon insertion of a workpiece between upper and lower bases is a typical example of the pressure mechanisms. The pressure mechanisms generally make use of water or oil pressures, a mechanical structure, or both of them.
An exciter or vibration generator is used to artificially generate vibration to investigate vibration characteristics of a structure. Exciters of an electromotive type and those employing an unbalance mass or a cam are known.
Because the conventional pressure mechanisms or exciters are generally of a complicated structure and are, hence, heavy and costly, light and inexpensive ones have been desired.